Diane James, the former leader of the UK Independence Party has quit the party, her office said.
James was leader of the party for just 18 days when she stepped down in October, citing personal reasons.
In a statement the 56-year-old said that her relationship with the party was "increasingly difficult" and that she quit as leader because she had "no support" from the party.
At a high profile public event in Cambridge last week, I was asked why I had not completed the process to become leader of Ukip. I had little option but to give the truthful response that, although nominated Leader by popular vote in the membership, I found I had no support within the executive and thus no ability to carry forward the policies on which I had campaigned. My decision to retire from the election process and not complete it was very difficult personally and professionally, given that Ukip has dominated my life and all my efforts for over 5 years. In recent weeks, my relationship with the Party has been increasingly difficult and I feel it is now time to move on. I wish the Party well for the future under new leadership.
James was elected as MEP for South-East England in 2014, and has now requested to be allowed to remain an independent in the European Parliament.
She said she would continue to serve constituents "effectively and diligently" for the rest of her five-year term.
This is the latest in a number of controversies involving the embattled political party in the wake of the EU referendum and Nigel Farage announcing that he would stand down.
It comes after the favourite for next leader Steven Woolfe quit the party in October, saying the party was "ungovernable" and "riddled with infighting" after he was punched in an altercation with another MEP.
Ukip is currently undergoing its second leadership contest this year, with Paul Nuttall, John Rees-Evans and Suzanne Evans vying for votes to become successor to Nigel Farage.
Results of the election will be announced on November 28.